chapman



(No Model.) 2 Sheets-Sheet 1.

W. CHAPMAN.

ELECTRIC MOTOR CONTROLLER.

No. 581,658 Patented Apr. 27. 1897.

lA/itmsnssas. Inventor.

m: uonms nzrzns, co, PHOTO-mun. WASHINGTON, n, c.

(No Model.) 2 Sheets-Sheet 2.

W. H.-OHAP1V[AN.

ELECTRIC MOTOR CONTROLLER.

Patented Apr. 27., 1897.

H I I all? Inventor.

Wm. era/ m Witn6888.

e. wfiewm UNITED STATES PATENT OFFICE.

\VILLIAM H. CHAPMAN, OF PORTLAND, MAINE, ASSIGNOR TO THE BELKNAP MOTOR COMPANY, OF SAME PLACE.

ELECTRl-O-EWOTOR CONTROLLER.

SPECIFICATION forming part of Letters Patent No. 581,658, dated April 27, 1897.

A li ati fil d February 24, 1896. Serial No. 580,434. (No model.)

T at whom, it may concern:

Be it known that I, \VILLIAM II. CHAPMAN, a citizen of the United States, residing at Portland, in the county of Cumberland and State of Maine, have invented a new and use ful Electric-Motor Controller, of which the following is a specification.

My invention relates to electric motors applied to the running of various kinds of maio chinerysuch, for instance, as elevator-hoistin g machinesand has for its object the gradual admission of the electric current to the motor, so that it may not start too suddenly and thereby cause undue strain on the motor and the machinery operated by it, and, furthermore, to secure a uniformity of results independent of the will of the operator. I attain these objects by the mechanism illustrated in the accon'ipanying drawings, in which Figure 1 is a side elevation of an electric motor having the controller mounted on its top. Fig. 2 is a plan view of the controller, the cover of the containing box being re moved. Figs. 3 and a are views, respectively, of the front and back of the reversing-switch mounted on the slate slab A, Fig. 2. Fig. 5 is a view of the automatic resistance shortcircuiting device, partly in elevation and partly in section. Fig 6 is a section of the slate F and of the resistance terminals mounted thereon, taken on the line so 1!} of Fig. 5, and is drawn to a larger scale. Fig. 7 is an elevation of one of the resistance- [ramesD E,Fig. Figs. 8 and 9 are enlarged views of the contact-blocks of the reversingswitch. Fig. 10 is a diagram of the windings on the motor and their connections with the controller and of the parts of the controller with each other.

Similar letters and figures refer to similar parts throughout the several views.

B is a cast-iron box mounted on the top of the motor O and serves to inelose and pro tect the working parts of the controller. 111- side of this box, near one end, is a set of resistance coils, which are made of German-silver wire wound in a spiral and stretched on two frames D and E, made of cast-iron, the ends of the spiralsbeingseeurcd to porcelain knobs Z) l), &c., attached to the frames D E by screws, as shown in Fig. 7. A row of the knobs is placed across near the top and near the bottom of each side of the frames, as shown. The frames D E are retained in position by lugs a a, cast onto the inside of the box B. All of the resistance-coils on both frames are connected in series with each other, and at some of the junctions of the coils with each other, as well as at the two extremes of the series, leading-wires are at tached to connect to the resistance terminals or segments that are mounted on the slab of slate F. The slate F is retained in place in the same manner as the frames D E by lugs cast onto the inside of the box B.

On the slate F are mounted a series of metallic segments 1 2 3 it, the, correspondingin number to the leading-wires from the series of resistance-coils, and all arranged in the are of a circle at whose center is the studll, which is mounted on a projection from the segment 1 and is preferably cast in one piece with it. Each one of the segments 1 2 3 1, (be, is secured to the slate F by two screws 0 and (Z. The screw (Z has an enlarged head, and has a hole drilled in it to receive one of the leadingwires from the resistance-coils and a screw c for clamping that wire.

I is a lever pivoted on the stud H and hav ing at one end a weight J, which may be adjusted to differentdistances from the center, and at the other end the stud K, which is slotted to receive the copper strips ff. The copper strips ffwtre very thin and pliable and have secured to them the contact-shoes IL 71/, made of carbon. The contact-shoes h 7t are pressed into contact with the circle of segments 1 2 3 it, the, by the springs g g, which are secured to stud K and clamped together with strips ff by screws at i.

M is a brass spool which is wound full of insulated copper wire N, whose two terminals are at l l.

G is an iron sheath extending from one end of the spool to the other and inclosing the wire N. The spool M is secured to the bottom of the box B by screws m m, and has at its lower end a ln'ojection, on which a thread is cut to receive the cylinder 0, closed at its lower end, a hole being cut in the bottom of the box 13 to admit the cylinder 0.

P is a cylindrical piece of iron forming the core of the coil of the solenoid and is normally situated so that its upper end is about twothirds of the way through the coil from the bottom toward the top. The core P fits loosely inside the spool M, and is connected at its upper end to the lever I through the bar L, preferably made of vulcanized fiber or some other insulating material. The bar L is pivotally connected both to the core I and to the lever I. At the lower end of the core I is attached the rod (1, to the lower end of which is secured the piston 0, which is made much smaller than the cylinder 0, in which it operates.

13 is a brass ring which rests normally on top of the piston 0, and tits the cylinder 0 more closely than does the piston o.

r is a pin driven through the rod q, and serves for a stop to keep the ring-p always within a limited distance from the piston 0.

At the bottom of the cylinder 0 is a spiral spring j, on which the piston 0 normally rests, the spring being stiff enough to support the weight of the core P and other parts attached. to it and to act as an elastic buffer, agains'st which the piston o strikes at the end of its downward movement. The cylinder O is normally filled about half full of some liquid, preferably glycerin, which acts to check the movement of the piston as it moves upward through it.

In the box 13 at the opposite end from the resistance-framesDE the reversing-switch mounted on the two sides of the slate A. The slate A is retained in position in the same manner as the slate F by lugs east onto the inside of the box B.

On one side of the slate A are mounted four brass blocks Q Q Q5 Q and on the other side of the slate are the four similar blocks Q Q Q One of these blocksis shown in detail in Figs. 8 and 0. Each one has two copper contact-strips s s inserted into the end of it and soldered, with a space between the two strips large enough to receive the knives t due, on the switch-levers. Each block also has tweholes u u to receive the wires connecting the blocks with each other and with the other parts of the apparatus, and screws or r for clamping these wires.

At each side of the slate A is a switch-lever mounted on the shaft S and insulated therefrom by fiber blocks B, placed on the four sides of the shaft, which is made square at this point to hold the lever more securely. Each switch-lever is composed of the two brass pieces T T and fourswiteh-lniives It t. The screws W serve to clamp the two pieces T 1 together and at the same time hold the fiber blocks R firmly in place on the square portion of the shaft and in the pieces T T.

The switch-knives t a" do, are pivoted at one end in the pieces T but have only a limited range of movement, and they are normally in the position shown in Figs. :3 and it and are pressed by the flat springs U U, sccured to the pieces T T, and when drawn out of their normal position by contact friction with the copper contact-strips s 5' they are forced back again immediately when the consenese tact is left, thus insuring a quick and sure breaking of the electrical connection of the knives with the contact-strips.

For mechanical convenience ofattaching the blocks Q Q. (1 &c., to the slate the position of the two levers is at right angles to each other, the one at the opposite side of the slate in Fig 3 being shown in dotted lines.

At .2' is a piece of brass secured to the slate A and having two screws for clamping wires. One of the screws clamps the flexible wire X, connecting it to the switch-lever on the same side of the slate A, and the other screw clamps a wire leading to the shnnt-wimling of the m o t or.

At a in dotted lines in Fig. 3 is another similar piece of brass mounted on the opposite side of the slate A and likewise has two clamp-screws, one clamping a wire connecting it to the switch-lever on that side and the other clamping a wire that leads to one terminal of the wire I: on the spool M.

The passes through the side of the shalt 0 box l3 and has at its outer end a lever Z," keyed to it and provided with a pin 7 and connecting-rod Y, by which motion may be communicated to it from any convenient seurce as, for instance, the rocker-shaft of an elevatorhoistor the lever may be moved directly by the hand of the operator.

It will be seen from the above description that the resistance-coils on frames D it, together with the segments 1 2 3 t, forming the terminals of the resistance-coils, and the lover I and OOll't'21ClJSllOCS71.71 constitute a startii'igrheostat and that the addition of the coil of wire N and core 1 together forming a solenoid, makes it a selfacting rheostat.

The various parts of the apparatushaving been coi'inected to each other and to the motor by wires in accordance with the diagram Fig. 10, the action of the apparatus is as follows: The connecting-rod Y is pushed, we will say, to the right. This causes the switchlcnives tand t to come in contact, respectively, with the copper contact-strips on blocks Q and Q", and at the same time on the other side of the slate the knives t and i come in contact with the copper contactstrips on blocks Q and By this means connections are established by which an electric current may pass through two distinct circuits. Onc circui is through the coil and the slruntnvinding of the motor and the other is through the resist ance on frames 1) E and through the armature and series field-coils ot' the motor. The current being thus established, the coil N begins to pull its core 1 upward and thereby moves the lover I and brings the carbon contactpieces successively in contact with the ments 1 2 E) at, do, which form the terminals of the resistance-coils, thereby short-circuiting the several resistance-coils in succession until when the top segment is touched by the carbon blocks the resistance is all short-circuited, and the motor is then running attnll speed. The movement is prevented from tak- IIO ing place too suddenly by the action of the glycerin in the cylinder 0, for as the piston moves up together with the core P the ring 13 is kept down onto the piston by its own weight as well as by the pressure of the air above, and it is allowed to move only to the extent of the leakage of glycerin past the ring and piston, and the rate of that leakage is previously adjusted to secure the right rapidity of movement by making the ring fit the cylinder more or less loosely. It now the rod Y is brought back to the normal position, with the lever Z vertical and the switch-knives disengaged from contact, the electrical circuits are broken, and the coil N loses its power, and the core P, together with its attached parts, drops by its own weight. The instant the downward movement of the piston 0 commences a pressure is produced on the glycerin below it which raises the ring 13 away from the piston and gives the glycerin a free channel to escape from below upward, and the rapidity of the downward movement is thereby greatly increased and the carbon contactblocks are quickly brought to the segment 1, where all the resistance is leftin circuit, ready for starting the motor again or revel-sin it. If the motor is to be reversed, the rod Y is pushed to the left. The switch-knives then engage with the opposite set of contact-strips, and the portion of current passing through the armature is thereby reversed, but the portion of current passing through the fieldm net windings and through the coil N remains the same as before, and, pulling the core upward, it gradually short-circuits the resistance-coils at a rate predetermined by the freedom of the ring 1) in the cylinder 0, and when the switch is turned to the off position the return movement of the carbon contact-blocks takes place very quickly and enables the apparatus to accomplish very sudden reversals of the motor as they may be called for by the reversingswitch.

Instead of using the resistance-coils on the frames D E in connection with the segments 1 2 3 4, &c., it would be feasible to wind the field-magnets of the motor itself with special coils of wire that should be connected with these segments. These coils would then perform the same office as the resistance-coils shown, and the operation would be substantially the same. The current in either caseis admitted gradually to the armature and the latter allowed to come to full speed only after the carbon contact-blocks have reached the last segment at the top. The weight J is intended to counterbalance part of the weight of the core P, so that the coil N may not have unnecessary work to do. The weight J is adjusted to a point on the lever I such that the weight of the core P and its attached parts is able to overcome the opposing force of the v weight J and of the friction of the carbon ment that cuts out the resistance is subject to the will of the operator, and if the operator happens to be in a hurry he will frequently turn the current on so quick as to do damage to the motor. My device removes the possibility of such damage, as it always acts alike and only as quick as is best for the motor. The diagram Fig. 10 represents my controlling device as applied to a motor having a shunt-winding and also a series winding on its field-magnet. The reversing-switch is in this case connected into the armature-circuit in the manner shown, so as to send the cur rent in one direction or the other through the circuit containing the armature and the set of resistance-coils in the controller-box and the contact-shoes and segments connected therewith, according as the lever Z is pushed to one extreme or the other of its movement, but not to reverse the current in the series winding of the motor, and at either extreme of movement of the lever Z the switch also closes the circuit containing the shunt-wind ing of the field-magnet and the coil N, and the current in this latter circuit is always in one direction whichever side the switch may be turned.

Referring to Fig. 10, the course of the current may be followed more in detail: Let B represent a battery or other source of electric current, having its two terminals connected to the two binding-posts C C on the motor. Suppose the rod Y and lever Z be pushed to the right. This causes the switchknives t and t to come in contact, respectively, with the copper contact-strips on blocks Q, and Q and at the same time on the other side of the slate theknives t and t come in contact with the copper contact-strips on blocks Q, and Q. The course of the current will then be as follows: Entering, we will say, by binding-post 0 it divides into two courses, one through the series winding on the magnet-pole I and the other through the series winding on the magnet-pole P and the two courses reunite in the wire a which leads it to contact-block Q and by wire 17 it reaches contact-block Q, thence through the switchknife t to the parts T T of the switch-lever. At this point the current divides into two unequal parts, which unite again at the switchlever on the farther side of the slate. The smaller portion of the current passes by the flexible wire X, brass strip ,2, and wire f to one end of the shunt-winding on the magnetpole P, then successively through the shuntwindings on the magnet-poles P, P P and I? and by wire f to the terminal I of the solenoid-coil N, through the coil Nto its other terminal Z, thence by wire 0 to the brass strip 5 on the farther side of the slate, and by a flexible wire similar to X it reaches the switchlever on that side. The larger portion of the current in the meantime is passing through switch-knife t contact-block Q wire A to segment 1, thence through the resistance-coils R R to the segment 9, thence by wire a to the commutater-brush B, through the armature, and out by brush B through the wire a contact-block Q, wire b contact-block Q and switch-knife t to the switch-lever on the farther side of the slate, where it reunites with the other portion of the current, as stated above. The whole current then passes through switch-knife t contact-block Oiwire b and wire a, and then it again divides, part passing through the series wire on the magnet-pole P and part through the series wire on the magnet-pole P and the two parts unite again at binding-post G which is connected to the other pole of the battery or source of current at B, thus completing the circuit and establishing electric currents in the field-coils and in the armature of the motor and in the solenoid.

In order to reverse the direction of rotation of the armature of an electric motor, it is only necessary, as is well known, to reverse the direction of the electric current through the armature, the current in the field-magnets remaining the same. These conditions are fulfilled when the lever Z is turned to the left, as will be seen, for this movement of Z brings the switch-knife 15 into connection with contact-block Q and switch-knife t with contact-block Q and on the other side of the slate it puts 15" in connection with Q and t with Q. The current entering by bindingpost 0 reaches the contact-block Q by the same course as before and there passes into the switch-lever by switch-knife t. It then divides, as before, the smaller portion passing the same way, as before, through the shuntfield and solenoid. The other portion goes through the switch-knife t contact-block Q, wire a to the commutator brush B and thence through the armature in the reverse direction to its former course, and out by brush B, through the wire a, segment 9, resistanceeoils R R segment 1, wire A contact-block Q wire b contactblock Q switclrknife t switclrlever on farther side of slate, switch-knife t contact-block Q, wire and wire a where it divides, as before, part through the series winding on the magnet-pole P and part through the series winding on the magnet-pole P to the hinding-post C Thus it will be seen that the current that passes through the shunt-winding of the field and through the solenoid and also the current that passes through the se ries winding of the field-magnet is in the same direction irrespective of which way the switch is turned, but the current through the armature is in one direction or the other according as the switch is turned one way or the other, and that whenever the current is established through the shunt-winding of the field the solenoid being in circuit with the shunt-field becomes energized and causes the contact-block h to move along the peripheral surface of the series of segments and finally to come into contact with the last segment 1) and so short-circuit all the resistance-coils and bring the motor to its full power. In order that the expenditure of energy in the so lenoid may be small, I have endeavored to avoid friction and to produce a sliding c011- tact device that should require a comparatively small solenoid to operate, and to this end I make the contact on the convex peripheral surface instead of on the end face of the segments, as is usual in rheostats, and I am thereby enabled to cluster the segments into a comparatively small circle. Experience has proved that this arrangement gives the most perfect contact with the least frict-ion.

\Vhat I claim as new, and desire to secure by Letters Patent of the United States, is-

1. In combination with an electric motor having a shunt-winding on its field-magnet, an electric switch arranged to make and break the circuit through said field-magnet and to reverse the current in the armature of said motor, a set of resistance-coils whose terminals are connected to a series of conductingsegments arranged in the arc of a circle, a contact-shoe arranged to move along the convex peripheral surface of said series of segments, a solenoid connected in series with the said shunt-winding and having its core arranged to operate said contact-shoe and bring it successively into contact with each of said segments, and a cylinder containing a piston and valve arranged to close during the on movement of the contact-shoe but to open during the reverse movement.

2. In combination with an electric motor having a shunt-winding on its field, a coil of wire connected in series with said shunt-windin g and having a vertically-movable iron core, a series of conducting-segments arranged in the arc of a circle and forming the terminals of a set of resistance-coils, a contact-shoe operatively connected to the upper end of said core and arranged to move in tangential contact with the peripheral surface of said series of segments, a piston and cylinder operatively connected to the lower end of said core, a ring placed loosely on the top of said piston and made to fit the cylinder more closelythan said piston adapting it to operate as a valve and to check the upward movement of the said core more than it does the downward movement.

WM. H. CHAPMAN.

Witnesses:

SETH L. LARRABEE, A. L. LOWELL. 

